Research On Downgrading Manufacturing Of Bolt Spare Parts Based On Selective Laser Melting Technology

The breech system is the core component of ground suppression equipment,which directly determines the continuity of the equipment’s combat firepower.Starting from the emergency repair needs on the equipment battlefield,the laser melting technology is applied to the breech spare parts support to accelerate the manufacturing time.To achieve this,a method of degrading the performance of the spare parts is adopted to speed up their formation.However,the inability to quantitatively judge the manufacturing quality of the degraded spare parts becomes a key issue.This article establishes a degraded manufacturing system based on spare part structural characteristics,stress state,and mechanical properties as indicators,and conducts research on degraded manufacturing of spare parts based on laser melting technology.Combining with the failure mode analysis of the breech components,the mechanical performance indicators of the degraded spare parts are determined.The degraded manufacturing performance index system is established based on spare part structural characteristics,stress state,and mechanical properties as primary indicators.Based on the selected forming equipment and materials,extreme structure forming experiments such as SLM suspended planes,circular holes,square holes,cylinders,square columns,and sharp corners are conducted to determine the maximum forming size of the spare part structural characteristics.Based on the Simufict Addictive software,three-dimensional transient models of typical breech spare parts under different degradation process parameters are established,and the residual stress state of the degraded spare parts under different laser power,scanning speed,scanning pitch,and layer thickness parameters is studied,laying a foundation for the evaluation of the degraded manufacturing performance of spare parts.A stress improvement method of "interlayer laser remelting" for spare parts is proposed to reduce residual stress and improve mechanical properties of the spare parts.Eighty groups of orthogonal experiments are conducted with laser power,scanning speed,scanning pitch,and layer thickness parameters,and the microhardness,tensile strength,wear rate,and impact toughness of the formed parts are tested.Based on the VSCode platform,the experimental data is selected and processed,and a mechanical performance prediction model based on BP neural network is constructed through model structure design and parameter design,achieving accurate prediction of the mechanical properties of spare parts from process parameters.Based on the established degraded manufacturing performance evaluation system,a degraded manufacturing performance evaluation model is constructed by using the fuzzy comprehensive evaluation method,which is determined by the evaluation index weight and membership matrix.Typical breech spare parts such as the firing pin,closing lever pulley,curved arm pulley,and bolt body stop bar are manufactured using degraded manufacturing parameters,and the mechanical properties of the printed parts are degraded verified based on the original part mechanical properties as the evaluation benchmark,proving the accuracy of the degraded manufacturing performance evaluation system.Through the above research work,a quantitative evaluation method for degraded manufacturing of spare parts based on laser melting is obtained,and ultimately,degraded manufacturing spare parts that meet emergency needs are obtained,providing corresponding technical support for improving the theory and application basis of breech spare parts degraded forming.